function foo() {
  console.log(this);
}

// foo();

var obj = {
  name: 'why',
  bar: foo,
};
obj.bar();

var obj2 = {
  name: 'lilei',
  obj1: obj,
};
foo.call(obj2);

obj2.obj1.bar();

obj.bar.call(obj2);

new obj.bar();
